I have special difficulty explaining to students the ad populum fallacy and the ad temperantiam fallacy. The problem is that public discourse as a whole is largely currently founded on these two fallacies. Pointing them out causes major cognitive dissonance. They tend to do a double take, and at first be incredulous.
This is precisely why it is vital to teach them. The fact that we do not teach the logical fallacies in every school is profoundly sinister. It allows us to be manipulated.
The “ad populum” fallacy is the notion that truth is a majority mandate. If everyone thinks something is true, that proves it is true: “everybody knows.” This is the very premise of “constructivism,” the currently dominant educational philosophy. Constructivism holds that all truth is “socially constructed.” Truth is whatever the majority of any given social group says it is, and accordingly varies between cultures. Which is why we get “cultural relativism” and the insistence that all cultures must be accepted to be equal. It is also why we get transsexualism: according to constructivism, if an interest group can just get everyone to agree that a man can become a woman, it is a fact. For this very reason, dissent cannot be tolerated.
This is why classroom teachers always want to break into small groups. They cannot teach; the group must decide. The current Vatican synod on synodality seems to be based on the same dynamic: there is no truth other than whatever the people in the pews want to hear. We all get to vote on whether the sun goes around the earth, or vice versa. In fact, until the time of Copernicus, according to this theory, the sun DID go around the earth. Galileo was dead wrong. Einstein was a lunatic. Slavery was perfectly moral in the US South until those meddling Yankees got involved.
Interestingly, based on constructivism, a bridge built in India by Scottish engineers, would probably collapse. Scottish mathematics and physics cannot work in India.
The “ad temperantiam” fallacy holds that, whenever there are two opposing views, the truth must lie in the middle. A popular view, as old as Delphi, but also already exploded in ancient times. This fallacy is implicit whenever people object to “extremists”; as if holding a view strongly proves it is wrong. This is perfectly illogical.
The “ad temperantiam” fallacy is also implied when people demand an immediate ceasefire and a negotiated settlement for, say, the war in Gaza or the war in Ukraine. As though the problem is always a refusal of both or either side to compromise.
If two people hold opposing views strongly, there is no reason to think that a position in the middle between the two, which perhaps no one holds or would argue, is more correct than either of them. If some people think the sky is blue, and some people think the sky is red, this is not proof that the sky is purple. If teacher thinks 2 + 2 = 4, and little Johnny thinks 2 + 2 = 7, this does not prove that 2 + 2 = 5.5. If some people believe the sun goes around the earth, and others that the earth goes around the sun, it does not follow that the heavenly bodies dance around each other. If one country invades another, it does not prove that they have a legitimate grievance, and their opponent is equally responsible for the war in pig-headedly defending themselves.
In the natural course of things, if there is a disagreement between two parties or two positions, one position is probably wrong, in error, and the other correct.
'Od's Blog: Catholic comments on the passing parade.
